Article of footwear with a lightweight foam midsole

ABSTRACT

An article of footwear is disclosed that includes an upper element and a sole structure secured to the upper element. The sole structure further comprises a midsole element that defines a plurality of indentations extending through a polymer foam material from a first surface to a second surface. The plurality of indentations comprising at least a first set of indentations and second set of indentations. The first set of indentations extending downwards from an upper surface; whereas, a plurality of second indentations extending upwards from a lower surface. The first set of indentations being offset from the second set of indentations.

FIELD OF THE INVENTION

The present invention relates to footwear. The invention concerns, moreparticularly, an article of footwear with a plurality of indentationsextending in a substantially vertical direction through a midsole.

BACKGROUND

A conventional article of athletic footwear includes two primaryelements, an upper and a sole structure. The upper and the solestructure operate cooperatively to provide a comfortable structure thatis suited for a variety of activities such as walking and running. Theupper provides a covering for the foot that securely receives andpositions the foot with respect to the sole structure. In addition, theupper may have a configuration that protects the foot and providesventilation, thereby cooling the foot and removing perspiration. Thesole structure is secured to a lower surface of the upper and isgenerally positioned between the foot and the ground. In addition toattenuating ground reaction forces, the sole structure may providetraction and control foot motions.

Current sole structure designs, however, provide a large portion of theoverall weight of the athletic footwear. Heavier athletic footweardirectly impacts comfort of the wearer and decrease performance during amultitude of activities such as running and walking. Current solestructure designs have focused on using lighter weight materials in thedesign of the sole structure to reduce the overall weight of theathletic footwear.

The sole structure of athletic footwear generally exhibits a layeredconfiguration that includes a comfort-enhancing insole, a resilientmidsole formed from a polymer foam material, and a ground-contactingoutsole that provides both abrasion-resistance and traction. The midsoleis the primary sole structure element that attenuates ground reactionforces and controls foot motions. Suitable polymer foam materials forthe midsole include ethylvinylacetate or polyurethane that compressresiliently under an applied load to attenuate ground reaction forces.Conventional polymer foam materials are resiliently compressible, inpart, due to the inclusion of a plurality of open or closed cells thatdefine an inner volume substantially displaced by gas. The polymer foammaterials of the midsole may also absorb energy when compressed duringambulatory activities.

The midsole may be formed from a unitary element of polymer foam thatextends throughout the length and width of the footwear. With theexception of a thickness differential between the heel and forefootareas of the footwear, such a midsole exhibits substantially uniformproperties in each area of the sole structure.

Therefore, there is a need in the art for athletic footwear thatovercomes the disadvantages of prior athletic footwear by providing awearer with a lightweight sole structure in order to reduce the overallweight of the athletic footwear.

SUMMARY

The invention relates to an article of footwear having an upper and asole structure secured to the upper. The sole structure includes amidsole element. The midsole element extends through a portion of alongitudinal length of the sole structure and from a lateral side to amedial side of the sole structure. The midsole element is formed from apolymer foam material and has a first surface and an opposite secondsurface. The midsole element defines a plurality of indentationsextending through the polymer foam material and from the first surfaceto the second surface. The midsole element having a plurality of firstindentations that extend downwards from an upper surface and a pluralityof second indentations that extend upwards from a lower surface, theindentations being offset from one another.

The indentation may extend in a substantially vertical direction andexhibit various shapes and configuration such as a hexagonal,triangular, square, pentagonal, or round, for example. The indentationsmay also form a tessellation or have a tapered structure. In an aspectof the invention, the dimensions of the indentations may vary throughoutthe midsole element.

The advantages and features of novelty characterizing the presentinvention are pointed out with particularity in the appended claims. Togain an improved understanding of the advantages and features ofnovelty, however, reference may be made to the following descriptivematter and accompanying drawings that describe and illustrate variousembodiments and concepts related to the invention.

DESCRIPTION OF THE DRAWINGS

The foregoing summary as well as the following detailed description,will be better understood when read in conjunction with the accompanyingdrawings.

FIG. 1 illustrates a lateral side elevational view of an article offootwear having a midsole in accordance with an aspect of the invention.

FIG. 2 illustrates a medial side elevational view of an article offootwear having a midsole in accordance with an aspect of the invention.

FIG. 3 illustrates a top view of a midsole in accordance with an aspectof the invention.

FIG. 4 illustrates another top view of a midsole in accordance with anaspect of the invention.

FIG. 5 illustrates a bottom view of the midsole shown in FIG. 3 inaccordance with an aspect of the invention.

FIG. 6 illustrates a bottom view of the midsole shown in FIG. 4 inaccordance with an aspect of the invention.

FIG. 7 illustrates an outsole in accordance with an aspect of theinvention.

FIG. 8 is a cross-sectional view of an embodiment of the midsole of theinvention as defined by section line AA in FIG. 4 in accordance with anaspect of the invention.

FIG. 9 is another cross-sectional view of an embodiment of the midsoleof the invention as defined by section line BB in FIG. 4 in accordancewith an aspect of the invention.

FIG. 10 illustrates a bottom view of an article of footwear with variousindentations of different sizes and shapes in accordance with an aspectof the invention.

FIGS. 11-17 are top plan views of portions of alternate midsoleconfigurations in accordance with in accordance with an aspect of theinvention.

FIG. 18 is top plan view of a midsole configuration illustratinghexagonal indentations having a greater variance in dimensionsthroughout the length of midsole in accordance with an aspect of theinvention.

DETAILED DESCRIPTION

The following discussion and accompanying figures disclose an article offootwear having a midsole element in accordance with the presentinvention. Concepts related to midsole element are disclosed withreference to footwear having a configuration that is suitable forvarious athletic activities, including running, for example. Theinvention is not solely limited to articles of footwear designed forrunning, however, and may be applied to a wide range of athleticfootwear styles that include basketball shoes, training shoes, walkingshoes, hiking shoes and boots, tennis shoes, volleyball shoes, soccershoes, and football shoes. In addition to athletic footwear, conceptsrelated to the invention may be applied to footwear that is generallyconsidered to be non-athletic (e.g., dress shoes, sandals, and workboots) or footwear serving a medical or rehabilitative purpose.Accordingly, one skilled in the relevant art will appreciate that theconcepts disclosed herein apply to a wide variety of footwear styles, inaddition to the specific footwear style discussed in the followingmaterial and depicted in the accompanying figures.

An article of footwear 100, as depicted in FIG. 1, includes an upper 120and a sole structure 130 that are suitable for a variety of athleticactivities, including running, for example. Upper 120 may have agenerally conventional configuration incorporating a plurality ofmaterial elements (e.g., textiles, foam, and leather) that are stitchedor adhesively bonded together to form an interior void for securely andcomfortably receiving a foot. The material elements may be selected andlocated with respect to upper 120 in order to selectively impartproperties of durability, air-permeability, wear-resistance,flexibility, and comfort, for example. Moreover, upper 120 may comprisea plurality of air slots (not shown) throughout upper 120 to increaseair flow through upper 120 and decrease weight of upper 120. Inaddition, upper 120 may include a lace that is utilized in aconventional manner to modify the dimensions of the interior void,thereby securing the foot within the interior void and facilitatingentry and removal of the foot from the interior void. The lace mayextend through apertures in upper 120, and a tongue portion of upper 120may extend between the interior void and the lace. Accordingly, upper120 may exhibit a substantially conventional configuration within thescope of the present invention. In addition, the upper 120 mayincorporate a sock liner (not depicted) that is positioned within theinterior void in upper 120 and located to correspond with a plantar(i.e., lower) surface of the foot, thereby enhancing the comfort offootwear 100.

For aid in describing various aspects of the invention, footwear 100 maybe divided into three general regions: a forefoot region 111, a midfootregion 112, and a heel region 113, as illustrated in FIG. 1. Forefootregion 111 generally includes portions of footwear 100 correspondingwith the toes and the joints connecting the metatarsals with thephalanges. Midfoot region 112 generally includes portions of footwear100 corresponding with the arch area of the foot, and heel region 113corresponds with rear portions of the foot, including the calcaneusbone. Footwear 100 also includes a lateral side 114 and a medial side214 (FIG. 2). Regions 111-113 and sides 114 and 214 are not intended todemarcate precise areas of footwear 100. Rather, regions 111-113 andsides 114 and 215 are intended to represent general areas of footwear100 to aid in the following discussion.

A moderation plate 135 may be positioned between the sole structure 130and the upper 120. Moderation plate 135 may comprise an upper portion137 and a lower portion 138. Moderation plate 135 may be comprised of afull nylon plate to provide additional support to the wearer of footwear100. Those skilled in the art will realize that moderation plate 135 maybe composed of other materials such as numerous polymers.

Sole structure 130 may include various elements such as a midsole 141and an outsole 143. Midsole 141 may include an upper midsole surface 151and a lower midsole surface 152. The upper midsole surface 151 may besecured to a lower portion 138 of moderation plate 135 and attenuateground reaction forces as sole structure 130 and the moderation plate135 are compressed between the foot and the ground.

Outsole 143 may be secured to a lower midsole surface 152. Outsole 143may be formed from a durable and abrasion-resistant material, such asrubber, that may be textured to define various protrusions for providingtraction. Although outsole 143 is depicted as a unitary elementextending through each of regions 111-113, in other aspects of theinvention outsole 143 may be two or more separate elements.

FIG. 2 illustrates a medial side elevational view 214 of footwear 100.As described above with respect to FIG. 1, footwear 100 includes anupper 120 and a sole structure 130 that are suitable for a variety ofathletic activities, including running, for example. For aid indescribing various aspects of the invention, footwear 100 may be dividedinto three general regions: a forefoot region 111, a midfoot region 112,and a heel region 113, as illustrated in both FIGS. 1 and 2.

As shown in FIG. 2, the forefoot region 111 may include at least onecrown 231 to provide additional resistant to abrasion. As those skilledin the art will realize, a wearer of footwear 100 may during certainathletic activities place additional force on the medial forefootportion of footwear 100. The inclusion of at least one crown 231 on themedial forefoot of footwear 100 may decrease wear on that portion offootwear 100.

As further illustrated in FIG. 2, moderation plate 135 may be positionedbetween the sole structure 130 and the upper 120. In various aspects ofthe invention, the entire moderation plate 135 may not be completelyvisible to an observer as midsole 141 may partially obscure moderationplate 135. In other aspects of the invention, moderation plate 135 maybe composed of various separate sections which may not be unitary inconstruction.

Midsole 141 may be formed from a polymer foam material, such aspolyurethane or ethylvinylacetate, that extends along at least a portionof the longitudinal length of footwear 100 (i.e., through regions111-113) and also from at least a portion of lateral side 114 to medialside 214. In certain aspects of the invention, midsole 141 may be formedfrom two or more discrete material elements (i.e., a forefoot elementand a heel element), or midsole 141 may be formed from a dual-densityfoam (i.e., lateral side 114 may be formed from a softer foam thanmedial side 214). In another aspect of the invention, dual-density foamin the form of foam inserts may be located in various portions ofmidsole 141. For example, midsole 141 may be comprised of foam inserts180 which are illustrated in FIGS. 1 and 2. The dual-density foam mayprovide a wearer with improved force attenuation properties.

In an aspect of the invention, various midsoles are depicted in FIGS.3-7. FIGS. 3 and 5 depict a midsole 350 which includes an upper midsolesurface 351 (FIG. 3) and an opposite lower midsole surface 552 (FIG. 5).A plurality of indentations 380 extend between the upper midsole surface351 and the opposite lower midsole surface 552. The plurality ofindentations 380 may extend through midsole 350 in a substantiallyvertical direction. In addition, midsole 350 may taper downward betweenheel region 113 and forefoot region 111. Moreover, in one aspect of theinvention, the number of indentations 380 in the forefoot region 111 maybe greater than a number of indentations 380 in a midfoot region 112 ora heel region 113 of midsole 350. In an alternative embodiment, thenumber of indentations in the heel region 113 may be greater than thenumber of indentations 380 in the midfoot region 112 or the forefootregion 111.

Midsole 350 may be manufactured through a molding process, wherein apolymer material is injected into a mold having the shape of midsole350. The various indentations 380 may be formed by projections thatextend between upper and lower portions of the mold. The configurationof indentations 380 may vary significantly within the scope of thepresent invention. For example, indentations 380 may exhibit constantdimensions between upper midsole surface 351 and lower midsole surface552. In another aspect of the invention, indentations 380 may exhibittapered dimensions between upper midsole surface 351 and lower midsolesurface 552.

For instance, FIGS. 4 and 6 illustrate an aspect of the invention inwhich a first set of indentations 680 are rectangular in shape. In FIGS.4 and 6, a midsole 450 is shown which includes an upper midsole surface451 (FIG. 4) and an opposite lower midsole surface 652 (FIG. 6). Theplurality of indentations 480 extend between the upper midsole surface451 and the opposite lower midsole surface 652. In addition, a secondset of indentations 680 offset from the first set of indentations 480may extend between the lower midsole surface 652 and the opposite uppermidsole surface 451. The plurality of indentations 680 may extendthrough midsole 450 in a substantially vertical direction. In addition,the plurality of indentations 680 may also have a tapered configuration.The tapered configuration of indentations 680 may be opposite of thetapered configuration of indentations 480. For example, FIGS. 8 and 9illustrate an aspect of the invention, wherein, indentations 680 have atapered configuration. In particular, FIG. 8 illustrates a cross sectionAA taken from FIG. 4 of midsole 450 in the forefoot region of thefootwear; whereas, FIG. 9 illustrates a cross section BB taken from FIG.4 of midsole 450 in the heel region. As may be seen in FIGS. 8 and 9,the dimensions of indentations 680 adjacent to upper midsole surface 451are less than the dimensions of indentations 680 adjacent to lowermidsole surface 652. That is indentations 680 may taper inward betweenlower midsole surface 652 and upper midsole surface 451. As shown inFIG. 4, the tapered indentations 482 may appear as circular penetrationsas they taper in dimension from lower midsole surface 652 to uppermidsole surface 451 (FIGS. 8 & 9).

In an aspect of the invention, tapered indentations such as indentations480 may not be visible on a lower midsole surface, such as lower midsolesurface 652, as an outsole may mask penetration of midsole 450. Theoutsole may be secured to the lower midsole surface. Outsole 143 may beformed from a durable and abrasion-resistant material, such as rubber,that may be textured to define various protrusions for providingtraction. For example, an outsole 702 as shown in FIG. 7 may hidepenetration of a plurality of indentations through a midsole from anupper midsole surface to a lower midsole surface. The coveredindentations may be offset by a plurality of indentations 780 extendingfrom a lower midsole surface to an upper midsole surface.

FIG. 10 illustrates another aspect of the invention in whichindentations may vary in size depending of the specific location of theindentations. In FIG. 10, a sole view of an article of footwear 1000 isillustrated in which the number of indentations 1180 in the forefootregion 1110 is greater than the number of indentations 1182 in a midfootregion 1120 or a number of indentations 1184 in a heel region 1130 offootwear 1000. Further as illustrated in FIG. 7, the indentations (1180,1182, and 1184) found on footwear 1000 may vary in shape and dimensionacross the various regions or within each of the regions. For example inforefoot region 1110, a first indentation 1130 may be wider than asecond indentation 1131. Similarly, indentation 1130 of forefoot region1110 may vary in shape and dimension from midfoot indentation 1132 orheel indentation 1134. The various sized indentations may be used tovary the weight of the footwear 1000 in specific regions in order toenhance overall performance of footwear 1000.

As those skilled in the art will realize, the shapes and sizes ofindentations may also vary significantly within the scope of the presentinvention to include numerous other shapes as depicted in FIGS. 11-18.For example, a midsole 40 may exhibit triangular or square shapeindentations 43, as depicted in FIGS. 11 and 12. An advantage oftriangular and square shapes relates to the manner in which the variousindentations 43 may be arranged. More particularly, indentations 43having hexagonal, triangular, or square shapes may be arranged toeffectively form a tessellation. As utilized herein, the term“tessellation” is defined as a covering of an area, without significantgaps or overlaps, by congruent plane figures of one type or a pluralityof types. Accordingly, indentations 43 having hexagonal, triangular, orsquare shapes, as viewed in either an upper surface or lower surface,may be arranged such that edges of the various indentations 43 areadjacent to edges of other indentations 43 and few significant gaps areformed between the indentations 43.

Indentations 43 also comprise a variety of other configurations andcombinations. Referring to FIG. 13 indentations having a mixture ofhexagonal, triangular, and square configurations are arranged to form atessellation. Indentations 43 having a chevron configuration or anirregular configuration may also be arranged to form a tessellation, asdepicted in FIGS. 14 and 15. Accordingly, indentations 43 may form atessellation when exhibiting non-regular geometrical or non-geometricalconfigurations. In other embodiments, indentations 43 may exhibitpentagonal or round configurations, as depicted in FIGS. 16 and 17.Accordingly, indentations 43 may exhibit a variety of configurationswithin the scope of the present invention.

Each of indentations 43 may exhibit similar dimensions or may also beconfigured to have a variety of dimensions. Referring to FIG. 18,midsole 40 defines a variety of indentations 43 with hexagonalconfigurations. Indentations 43 exhibit a greater variance in dimensionsthroughout the length of midsole 40. In heel region 113, one ofindentations 180 is significantly larger than other indentations such asindentation 185. The larger indentation 180 is positioned to correspondin location with a calcaneus bone of a foot. That is, the largerindentation 180 will be generally positioned under the calcaneus bone ofa foot. This configuration may be utilized, for example, to impartgreater compliance to heel region 113 of midsole 40 and particularly thearea under the calcaneus.

In addition, different shapes and dimensions of indentations may be usedin the various different regions of the article of footwear to impartvarious advantages to and article of footwear. For example, usingdifferent patterns and sizes of indentations may decrease thecompressibility of specific areas of a sole structure or impartadditional stability or otherwise control foot motions, such as thedegree of pronation. For example, it is well know in the art that thetypical motion of the foot during running proceeds as follows:Initially, the heel strikes the ground, followed by the ball of thefoot. As the heel leaves the ground, the foot rolls forward so that thetoes make contact, and finally the entire foot leaves the ground tobegin another cycle. During the time that the foot is in contact withthe ground and rolling forward, it also rolls from the outside orlateral side to the inside or medial side, a process called pronation.While the foot is air-borne and preparing for another cycle, theopposite process, called supination, occurs. In order to impart asuitable degree of ground reaction force attenuation upon contact of theheel with the ground, various positioned and sized indentations may beplaced in heel region of the article of footwear. Also, to increasestability and the control of foot motions, the relative location andsize of the indentations may be utilized throughout the forefoot andmidfoot regions of the article of footwear.

The present invention is disclosed above and in the accompanyingdrawings with reference to a variety of embodiments. The purpose servedby the disclosure, however, is to provide an example of the variousfeatures and concepts related to the invention, not to limit the scopeof the invention. One skilled in the relevant art will recognize thatnumerous variations and modifications may be made to the embodimentsdescribed above without departing from the scope of the presentinvention, as defined by the appended claims.

1. An article of footwear comprising: an upper; a solid moderation plateattached the upper, the solid moderation plate having a top surface anda bottom surface; and a sole structure comprising: a midsole having afirst surface and an opposite second surface, the midsole elementextending substantially through a longitudinal length of the solestructure and from a lateral side to a medial side of the solestructure, the midsole element defining a plurality of indentationsextending through the polymer foam material and from the first surfaceto the second surface; and an outsole attached to the opposite secondsurface.
 2. The article of footwear recited in claim 1, wherein theindentations have a hexagonal shape.
 3. The article of footwear recitedin claim 1, wherein a shape of the indentations is selected from a groupconsisting of triangular, square, pentagonal, and round.
 4. The articleof footwear recited in claim 1, wherein the indentations form atessellation.
 5. The article of footwear recited in claim 1, wherein theindentations are tapered.
 6. The article of footwear recited in claim 1,wherein dimensions of the indentations vary throughout the midsoleelement.
 7. The article of footwear recited in claim 1, wherein theindentations have a substantially vertical orientation.
 8. The articleof footwear recited in claim 1, wherein the plurality of indentationscomprises conical indentations.
 9. An article of footwear having anupper, a moderation plate, and a sole structure, the sole structurecomprising: an outsole; and a midsole, the midsole in contact with themoderation plate and the upper, the midsole having a plurality of firstindentations that extend downwards from an upper surface and a pluralityof second indentations that extend upwards from a lower surface, theplurality of first indentations being offset from the plurality ofsecond indentations.
 10. The article of footwear recited in claim 9,wherein the moderation plate comprises a solid moderation plate.
 11. Thearticle of footwear recited in claim 9, wherein the indentations have ahexagonal shape.
 12. The article of footwear recited in claim 9, whereina shape of the indentations is selected from a group consisting oftriangular, square, pentagonal, and round.
 13. The article of footwearrecited in claim 9, wherein the indentations form a tessellatedconfiguration.
 14. The article of footwear recited in claim 9, whereinthe indentations are tapered.
 15. The article of footwear recited inclaim 9, wherein dimensions of the indentations vary throughout themidsole element.
 16. The article of footwear recited in claim 9, whereinthe indentations have a substantially vertical orientation.
 17. Anarticle of footwear comprising: an upper; a solid moderation plateattached to the upper, the moderation plate having a top surface and abottom surface; and a sole portion attached to the bottom surface of themoderation plate, the sole portion comprising: an outsole; and amidsole, the midsole having a plurality of first indentations thatextend downwards from an upper surface and a plurality of secondindentations that extend upwards from a lower surface, the plurality offirst indentations being offset from the plurality of secondindentations.
 18. The article of footwear recited in claim 17, whereinthe indentations are oriented to be substantially vertical.
 19. Thearticle of footwear recited in claim 17, wherein a shape of theindentations is selected from a group consisting of triangular, square,and hexagonal.
 20. The article of footwear recited in claim 17, whereinthe indentations are tapered.